United and Liverpool are the two most successful teams in English football but have won only one league title each in the past decade.
"You get a lot of money from the Premier League, from broadcasting and sponsorship, but you also have to put a lot of money in to keep your team."
"The failure of the proposal and the failure of Premier League clubs to gain greater power in the running of the league are likely influencing factors," said Spencer Harris, Associate Professor of Sport Management at the University of Colorado.
"The current owners (of Liverpool and United) don't have the finances to compete and invest on the level of these other clubs."
"(There is a) general realisation that English Premier League teams, the two biggest ones per se, are relatively uncapitalized versus NFL franchises, which have been a barometer for a longer period of time."